I recently gave a talk at the Australian Python Convention arguing that for big decisions, it can be risky to rely on business case analysis prepared on spreadsheets, and that one alternative is to use Python with pandas.
The video is available here.
You can see the slides from the talk online here.
I also showed an ipython notebook, which you can find as a pdf here. The slides, the ipython notebook, and the beginnings of a library to make the analysis easier, are all at bitbucket.org/artstr/montepylib.